Softening apparatus in tandem electric wire manufacture

ABSTRACT

A softening apparatus employed in the heat treatment step in a tandem electric wire manufacturing process wherein wire drawing, heat treating, extrusion coating, cooling and take-up steps are performed in tandem, for softening a core wire including a tension stabilizing mechanism for setting the tension of core wire in the heat treating step independently of the tension of the core wire in the subsequent steps being formed of a first dancer roller, a second dancer roller and a first capstan positioned between the first dancer roller and the second dancer roller, a softening mechanism for elevating the temperature of the core wire to its softening temperature being positioned in advance of the first dancer roller and a reheating mechanism for reheating the softened core wire being positioned between the first dancer roller and the first capstan.

Sugano et al.

[11] 3,821,511 June 28, 1974 SOFTENING APPARATUS IN TANDEM ELECTRIC WIRE MANUFACTURE Inventors: Katsumi Sugano; Yoshio llkegami;

Hirohumi Kimura, all of Kobe, Japan Assignees: Kobe Steel, Ltd., Kobe; Sumitomo Electric Industries, Ltd., Osaka, both of, Japan Filed: Mar. 7, 1973 Appl. No.: 338,870

Foreign Application Priority Data Mar. 7, 1972 Japan 47-23782 U.S. Cl. .219/155 Int. Cl C2ld 9/62 Field of Search 219/l0.61, 155, 388;

References Cited UNITED STATES PATENTS 9/1946 Walton et al. 219/155 X 3/1952 O'Grady 4. 219/155 3,515,848 6/1970 Heinz 219/155 Primary Examiner-C. L. Albritton Attorney, Agent, or Firm-Oblon, Fisher, Spivak, Mc- Clelland & Maier [57] ABSTRACT A softening apparatus employed in the heat treatment step in a tandem electric wire manufacturing process wherein wire drawing, heat treating, extrusion coating, cooling and take-up steps are performed in tandem, for softening a core wire including a tension stabilizing mechanism for setting the tension of core wire in the heat treating step independently of the tension of the core wire in the subsequent steps being formed of a first dancer roller, a second dancer roller and a first capstan positioned between the first dancer roller and the second dancer roller, a softening mechanism for elevating the temperature of the core wire to its softening temperature being positioned in advance of the first dancer roller and a reheating mechanism for reheating the softened core wire being positioned between the first dancer roller and the first capstan.

1111 Claims, 13 Drawing 1F igures SOFTENING APPARATUS IN TANDEM ELECTRIC WIRE MANUFACTURE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to softening apparatus employed in the heat treating step of a tandem electric wire manufacturing process wherein the wire drawing, heat treating, extrusion coating, cooling and take up steps are performed in tandem, and in view of the fact that whereas a high tension is necessary in the heat treating step, a tension as low as possible is required in the take-up step, the improvement of a dancer roller and capstan being combined in a specific relationship for setting the tension in the heat treating step independently of the tension in subsequent steps to thereby make good heat treatment and high speed production possible.

2. Description of the Prior Art A tandem electric wire manufacturing equipment will first be described with reference being made to FIG. 1 of the drawings. In the Figure, A is a take-up machine driven by a motor M2 having a controlled speed which rotates at a constant speed corresponding to a signal manually set in a setter B to take up a wire C at a constant speed. D is a wire drawing machine driven by another motor Ml having a speed control, and E is a dancer roller which stores wire of a fixed length between the wire drawing machine D and the take-up machine A, the stored amount being detected by a displacement detector F. The wire drawing machine D rotates at a speed corresponding to a signal comprising the sum of signal set by the setter B and the output signal of the displacement detector F.

The output signal of displacement detector F is set so as to be negative when the stored length in the dancer roller E is larger than a predetermined length and positive in the opposite case. That is, dancer roller E detects an integrated value of difference between the speed of the wire C coming out of the wire drawing machine D and the speed of the wire C being taken up by the take-up machine A to provide a follow-up con trol of wire drawing machine D with respect to take-up machine A.

Further, a heat treating process station G is provided between wire drawing machine D and dancer roller E to thereby anneal or preheat the running wire C by passing a current therethrough. The current fed to the wire C is performed, for example, by contacting a feeding sheave and wire C in a direct feeding system or by shorting the wire C on the sheave in an induction heating system. The wire C leaving dancer roller E is passed through an extrusion coating process H to provide thereon an insulation coating, and is then cooled in a cooling water vessel I.

However, in such conventional manufacturing equipment being described herein, with an increase in the wire speed, the tension increase in dancer roller E, the extruder H and the cooling water vessel 1 also is en hanced. Therefore. the tension of wire C entering takeup machine A increases, and when a certain speed is exceeded, the core may be elongated or broken to thereby cause a degrading of the quality thereof.

Also, when the weight on dancer roller E is reduced to keep the tension of wire C entering take-up machine A below a fixed value, the tension at the outlet of the heat treating process station G decreases, and the contact pressure between the sheave and the wire is re duced, which may cause sparking thereby, resulting in breaking of the wire. Also, due to the limitation of tension increase in dancer roller E, the extruder H and the cooling water vessel I to below the fixed value, the wire speed is undesirably maintained below a fixed value, and also, the treatment in the heat treating process station G becomes incomplete.

SUMMARY OF THE INVENTION The present invention has been accomplished to eliminate the aforementioned problems of the prior art and is directed to provide an apparatus which prevents the breakage and quality degradation of electric wire in so-called tandem wire manufacturing apparatus,

wherein the electric wire is produced by passing it progressively through the series of steps of wire drawing, heat treatment, coating, cooling and take-up.

More particularly, it is an object of the present invention to provide an apparatus which will stabilize tension of the wire in the heat treatment step and the subsequent steps of manufacture and improve the heat treatment thereof. Therefore, the present invention is characterized in the provision of a tension stabilizing mechanism for setting the core wire tension in the heat treatment step independently of the core wire tension in the subsequent steps, being in the form of a softening apparatus provided with a first dancer roller, a second dancer roller and a first capstan between the first and second dancer rollers.

The foregoing objects and others are attained by the present invention through the provision of a softening mechanism for softening the core wire before a first dancer roller increases the contact pressure between the sheave required to pass current through the core wire and the core wire to thereby attain a satisfactory softening, a reheating mechanism for reheating the softened core wire between the first dancer roller and a first capstan to remove water drops adhered to the core wire and heat the wire core to a temperature adapted to provide thereon an extrusion coating, a hot air generator between the first capstan and a second dancer roller and a heat insulating wall enclosing the first capstan and the second dancer roller prevent the reheated core wire from being cooled by the first capstan and the second dancer roller, and a second motor and a second stepless speed change gear for driving the first capstan separately from a first motor and a first stepless speed change gear for driving the heating mechanism. By controlling the first motor or the first stepless speed change gear by variation in the first dancer roller and by controlling the first and second motors or the first and second stepless speed change gears by variation in the second dancer roller, the peripheral speed of the sheave of the first capstan can be made greater than the sheave peripheral speed in the heating mechanism and reheating mechanism, and the contact pressure between the sheave in the heating and reheating mechanisms and the core wire can be increased to thereby prevent generation of spark and breaking of the core wire thereby, and further, since the core wire tension beyond the first capstan can be lowered, it becomes very easy to prevent the core wire from elongating and breaking in the vicinity of the take-up machine. The additional provision of a clutch selectively connecting the first stepless speed change gear and the second stepless speed change gear makes the wire setting operation at the start-up an easy procedure.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description, when considered in connection with the accompanying drawings, wherein like reference numerals and characters designate like or corresponding parts throughout the several views, and in which:

FIG. 1 is a schematic illustration of a conventional tandem coated wire manufacturing apparatus;

FIG. 2 is a schematic view of the softening apparatus of the present invention;

FIG. 3 shows the driving system for the softening apparatus of the FIG. 2;

FIG. 4 shows the sheave axis taken along the line A-A of FIG. 2;

FIG. 5 shows the softening machine body, softening upper shaft and softening lower shaft of the invention;

FIG. 6 shows the softening machine body taken along the C-C of FIG. 5;

FIG. 7 shows the first dancer roller taken along the line CC of FIG. 2;

FIG. 8 shows the first dancer roller body taken along the line H-H of FIG. 7;

FIG. 9 shows the reheating upper and lower sheave shafts taken along the line DD of the FIG. 2;

FIG. 10 shows the first capstan shaft and the second dancer roller taken along the line EE of FIG. 2;

FIG. 11 shows the second dancer roller body taken along the line 1-] of FIG. 10;

FIG. 12 shows the intermediate shaft taken along the line FF of FIG. 3; and

FIG. 13 shows another embodiment of the second dancer roller as an apparatus for manufacturing coated wire for communication cable.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and particularly FIGS. 2 and 3 thereof, a hard copper core wire W1 drawn by a wire drawing machine 1 contacts a preheating sheave or pulley 4 disposed in a frame 2 of the softening apparatus through a wire drawing finishing capstan 3, and passes through fixed guide rollers 5 and 6 and an adjusting guide roller 7, and moves about a softening upper sheave 8 and then about a softening lower sheave 9, and turning therefrom, through a softening upper guide sheave 10 contacts a first dancer roller upper sheave 11 which is the first dancer roller apparatus of the system. After contacting sheave 11, the core wire turns twice to the first dancer roller lower sheave l2, and then contacts a reheating lower sheave l4 and a reheating upper sheave 13, which constitute the reheating apparatus, and then contacts a front sheave 15, which is the firstcapstan apparatus. and after turning twice to a rear sheave 16, contacts an upper sheave 17, which is the second dancer roller apparatus. The core wire then turns twice to a lower sheave l8, and through a guide roller 19 to the next step of extrusion coating and the subsequent steps to obtain an insulation coated wire for product use as communication cable.

In FIG. 3, 20 is a first motor for driving the wire drawing machine 1, the preheating apparatus and the softening mechanism during normal operation, 21 is a second motor for driving the reheating apparatus and the first capstan apparatus during normal operation, and 22 is a first stepless speed change gear for adjusting the peripheral speed of the sheave of the wire drawing machine and the softening mechanism. A second stepless speed change gear 23 for adjusting the peripheral speed of the sheave of the reheating apparatus and the first capstan apparatus is provided, as is a speed change gear 24 for reversing the direction of rotation of the softening mechanism sheave and the reheating sheave. The numeral 25 is a preheating sheave shaft, 26 and 27 are the softening upper and lower sheave shafts respectively, 28 is a reheating upper sheave shaft, and 29 is a reheating lower sheave shaft. Capstan front and rear shafts 30 and 31 support the sheaves l5 and 16, while 32 is an intermediate shaft.

As clearly seen from both Figures, the finishing capstan 3 of the wire drawing machine I is supported on an intermediate shaft 33, the preheating sheave 4 is supported on shaft 25, the softening upper sheave 8 and guide sheave 10 are supported on shaft 26, and the softening lower sheave 9 is supported on shaft 27. The upper sheave ll of the first dancer roller is supported on a shaft 34 fixed to the frame 2, the lower sheave I2 of the first dancer roller is supported on a shaft 36 fixed to a body 35 of the first dancer roller movable up and down on the frame 2. The reheating upper sheave I3 is supported on the shaft 28, reheating lower sheave I4 on shaft 29, the front sheave 15 of the first capstan is supported on shaft 30, and the rear sheave 16 of the first capstan and the upper sheave 17 of the second dancer roller are supported on the shaft 31. The lower sheave 18 of the second dancer roller is supported on a shaft 38 fixed to a body 37 of the second dancer roller which is movable up and down on the frame 2.

Instead of the second dancer roller described above, another type of dancer roller shown in FIG. 13 may be usable in the tension stabilizing mechanism, in which instance a detector 126 is shown for detecting speed or tension of the wire between sheaves l6 and 19 and for controlling the driving systems thereof.

The above process will now be more particularly described. For the convenience of description, the steps of wire W1 being fed from wire drawing machine 1 through the first dancer roller apparatus will be first described.

In FIGS. 2 through 6, the preheating sheave is formed of a material having good conductivity and, as shown in FIG. 4, is disposed so as to rotate with shaft 25 which is rotatably mounted through bearings 40 on housing 39 in the frame 2 through a current feeding ring 41 at one end of the shaft 25, being connected to a current feeding brush 44 fixed to current feeding ring 41 through a shaft 43 of an insulator projecting from a current feeding brush support 42 fixed on the housing 39. To the other end of shaft 25 is attached a timing pulley 45, and around the pulley 45 a timing belt 46 runs.

In FIG. 5, the softening upper sheave 8 is shown being supported on one end of the softening upper sheave shaft 26, which is supported at one end by bearings 49 in a housing 48 mounted through insulators 47 on the machine body in the frame, so as to rotate with the shaft 26 through a current feeding ring 50 affixed thereto, and the softening upper guide sheave is mounted through a bearing 51 on the end of shaft 26 outside the sheave 8. A current feeding brush 54 is fixed to the current feeding ring 50 through an insulating brush shaft 53 which projects from a support 52 fixed on the housing 48. A timing pulley 55 is fixed to the other end of sheave shaft 26, and a timing belt 56 runs around the pulley 55.

In the same manner as just described with respect to sheave 8, the softening lower sheave 9 is fixed through a current feeding ring 59 to one end of shaft 27 rotatably supported on a housing 57 through bearings 58, and the ring 59 is connected to a current feeding brush 60 through a support 61 provided on housing 57 and a brush shaft 62, and a timing pulley 63 is fixed to the end of shaft 27 with a timing belt 64 beingturned around It.

The softening upper and lower sheaves 8 and 9 are positioned in an opposed relationship in the vertical direction, and softening tubes 65 and 66 are provided therebetween.

The softening tubes 65 and 66, as shown in FIGS. 5 and 6, have cooling and softening chambers 67 filled with an oxidation preventing agent, such as water vapor, water or inert gas, to prevent oxidation of the hard copper core wire W1, and are connected by a clamp 68 and operable by means of a hinge 69. A packing 70 is provided to prevent leakage of the oxidation preventing agent.

The softening process by preheating of hard copper .core wire W1 into soft cooper core wire W2 will now be described. When hard copper core wire W1 is drawn by the wire drawing machine 1 and is fed to and contacted with the softening upper sheave 8, as described above, a positive, or plus, power source is applied to the current feeding brush 54 and a current is passed through core wire W1 through current feeding ring 50 and the softening upper sheave 8, which is grounded through preheating sheave 4, current feeding ring 41 and current feeding brush 44, as shown in FIG. 4. When the current passes through the core wire W1, the temperature of wire W1 increases to a preheating temperature by electric resistance, and control of the preheating temperature is attained by the vertical movement of guide roller 7.

The core wire W1 contacted with softening upper sheave 8 passes through softening tubes 65 and 66 to contact the softening lower sheave 9, and then turns to pass again through softening tubes 65 and 66, andis fed through softening guide sheave 10 as soft copper core wire W2. More particularly, when the direct current plus" power source is applied to the softening upper current feeding brush 54, as described above, current passes through the hard copper core wire W1, and it enters softening lower sheave 9, and is grounded through current feeding ring 59 and current feeding brush 60. Thus, when the current passes through core wire W1, its temperature is raised to a softening temperature by electric resistance, and the hard copper core wire W1 then becomes soft copper core wire W2. It is because of the high temperature involved in this softening step that the cooling and softening chambers 67 filled with the oxidation preventing agent are provided in the softening tubes 65 and 66. That is, since core wire W1 exposed to air at the softening temperature oxidizes and loses its brightness, the softening temperature is lowered by filling the cooling chambers 67 with cooling water.

The soft copper core wire W2 obtained from the hard copper core wire W1, as described above, is further driven by the first dancer roller apparatus.

This first dancer roller apparatus will now be described with reference to FIGS. 2, 7 and 8.

The soft copper core wire W2 leaving softening guide sheave 111 contacts upper sheave 11 of the first dancer roller, and turns twice around sheave 12 provided in the first dancer roller body 35, which is vertically movable, and then is fed toward the reheating sheave 14.

More particularly, as shown in FIG. 7, the first dancer roller upper sheave 11 is rotatably supported through a bearing 71 on shaft 34 fixed to frame 2. On the lower side of frame 2 opposing the upper sheave 11 is mounted the first dancer roller body 35 which is vertically movable along the frame 2. That is, as shown in FIG. 8, frame 2 is provided with a recessed portion 72, on each front portion of the side walls of which is fixed a guide rail 73, and a guide roller 74 rolling on the rail 73 is provided on each side of body 35. Shaft 36 extends from the body 35, and the first dancer roller lower sheave 12 is rotatably supported on the shaft 36 through a bearing 75. When the body 35 moves from its standard position in normal operation, a positive or negative rotation signal, corresponding to its upward or downward movement respectively, is provided together with a rotation signal from the second dancer roller to the wire drawing machine 1 and the first motor 20 for driving the softening apparatus or the first stepless speed change gear 22 to thereby control the speed.

Furthermore, in order to maintain the outlet contact pressure of core wire at the softening lower sheave 9 and the inlet contact pressure of core wire at the reheating lower sheave 14 in a proper range with the tension of soft copper core wire W2, a weight 76 is provided in the lower portion of body 35, with its adjustment being possible. Furthermore, the vertically displaced position of the body 35 can be detected by a detector 77. That is, a pair of brackets 78 are provided on the upper and lower portion of the recessed portion 7 2, and the upper bracket 78 has a short shaft 79 and the lower bracket 78 has a bevel gear 80, and a rotary cylinder 82 is mounted therebetween with a cam 81 having a required torsional angle over its length. The cam 81 on the cylinder 82 engages with a pair of cam rollers 83 projecting backwardly from body 35, and when the parts 12, 76, etc. provided in body 35 move vertically as a whole, the cam rollers 83 operate along the torsional angle of the cam 81 to thereby rotate the rotary cylinder 82 about its central axis, this rotation being transmitted to a shaft 85 having a bevel gear 84 engaging with bevel gear 88, and further transmitted through a spur gear 86 provided on the other end of the shaft 85 to a spur gear 87 of the detector 77. Thereby, the vertically displaced position of the first dancer roller body 35 is detected by detector 77.

The core wire W2 from the first dancer roller apparatus is then fed to a reheating apparatus. This reheating apparatus is shown in detail in FIG. 9. That is, reheating upper sheave 13 is mounted on shaft 28 rotatably supported through bearings 98 on a housing 89 which is mounted through insulators 88 on the machine body frame 2. That is, on one end of shaft 28 is fixed a current feeding ring 91 on which sheave 13 is fixed, while a timing pulley 92 is fixed to other end of the shaft 28.

A current feeding brush 93 is fixed to current feeding ring 91, and the brush 93 and a support 94 mounted on housing 89 are connected together by a brush shaft 96.

On the other hand, reheating lower sheave 14 is fixed on a current feeding ring 98 which in turn is fixed on one end of shaft 29 supported through bearings 97 on a housing 96, and rotates together with the shaft 29. The fixed current feeding ring 98 and housing 96 are provided with a current feeding brush 99, the shaft 100 of which and a support 101 therefor being disposed in the same manner as described above, and when a direct current plus" power source is applied to the reheating upper current feeding brush 93, a current is passed through core wire W2 being in contact therewith through the current feeding ring 91 and sheave 13, and the current enters reheating lower sheave 14 to be grounded through current feeding ring 98 and current feeding brush 99. When the current passes through core wire W2, the temperature of the core wire W2 entering the extrusion coating station H rises to the optimum temperature therefor because of electric resistance, and water drops which were adhered to core wire W2 are thus removed, thereby contributing to an improvement in coating of insulating material in the cross head. Further, the second motor 21 (FIG. 3) for driving the reheating apparatus and the first capstan apparatus and a belt wheel 103 for obtaining power therefrom by V-belt 102, together with a timing pulley 104, are fixed on the other end of shaft 29. A timing belt 105 runs around the pulley 104 and pulley 92 of the upper shaft 28.

Furthermore, a timing pulley 106 is also fixed to the shaft 29, and a timing belt 107 thereon engages in tension with the second stepless speed change gear 23 for adjusting the peripheral speed of the sheaves of the reheating apparatus and the first capstan apparatus. Also, a clutch 112 is fixed to a shaft 111 which supports a V- pulley 110 having a V-belt 109 therein for driving the softening apparatus and the speed change gear 24 for reversing the direction of rotation of the reheating apparatus, and the clutch 112, for making the wire setting operation more easy, is provided in the middle of the driving system, to be described in detail hereinafter, so as to drive the wire drawing machine 1, the softening apparatus, the preheating apparatus, the first capstan apparatus and the reheating apparatus as a whole.

The soft copper core wire W2 leaving the reheating lower sheave l4'of reheating apparatus is then fed into the first capstan apparatus. That is, the soft copper core wire W2 from sheave l4 enters front sheave 15 of the first capstan, and turns twice around the rear sheave 16 of the first capstan, and then goes out to the upper sheave 17 of the second dancer roller. In this case by making the peripheral speed of each of the sheaves l and 16 of the first capstan greater than the peripheral speed of the reheating lower sheave 14 by means of the second stepless speed change gear 23 in FIG. 3, the contact pressure of the soft copper core wire W2 at the outlet of the reheating lower sheave 14 is increased to thereby prevent any generation of spark due to improper contact.

Referring now to FIG. showing the first capstan apparatus, front sheave thereof is fixed to shaft 30, and to the other end of the shaft are fixed timing pulleys 113 and 114, the shaft 30 being rotatable through bearings 115 in a housing 116.

The rear sheave 16 of the first capstan apparatus is fixed to shaft 31, and to the other end of the shaft 31 is fixed a timing pulley 117, the shaft 31 being rotatable through bearings 118 in a housing 119. Also rotatably supported on the shaft 31, outside the rear sheave 16, is the upper sheave 17 of the second dancer roller. A timing belt 120 for the reheating apparatus and the first capstan apparatus runs around the pulley 114 and a timing belt 121 runs around pulleys 114 and 117.

Thus, when power is transmitted to timing pulley 113 from the reheating apparatus by means of timing belt 120, and front sheave 15 of the first capstan is driven by shaft 30, timing pulley 114 is driven together with timing pulley 113 to thereby transmit power to timing pulley 117 through timing belt 121, and rear sheave 16 of the first capstan is thereby driven. The soft copper core wire W2 is increased in speed such that the peripheral speed of front sheave 15 and rear sheave 16 of the first capstan is increased over the peripheral speed of the reheating lower sheave 14 by means of the second stepless speed change gear 23, shown in FIG, 3, and thus taken up, and the outlet contact pressure of the soft copper core wire W2 at the reheating lower sheave 14 is increased in the range of proper tension of soft copper core wire W2 to thereby eliminate spark problems at the exit from the reheating lower sheave 14.

Below upper sheave 17 of the second dancer roller is provided lower sheave 18 of the second dancer roller with vertical movement thereof being allowed, the second dancer roller apparatus being constructed of similar members to those of the first dancer roller apparatus.

That is, on the lower portion of frame 2 opposing the sheave 16, there is mounted the second dancer roller body 37 which is vertically movable along the frame 2. That is, as shown in FIG. 11, the frame 2 is provided with a recessed portion 122, on the front portions of both side walls of which guide rails 123 are fixed, and guide rollers 124 rolling thereon are rotatably provided on both sides of the body 37. Shaft 38 is fixed to and projects from the body 37 for rotatably supporting the lower sheave 18 of the second dancer roller. When the body 37 moves from its standard position in normal operation, a positive or negative rotation signal, corresponding to its upward or downward movement, respectively, is given to the wire drawing machine 1 and the first motor 20 or the first stepless speed change gear 22, and further the same signal is given to the second driving motor 21 or the second stepless speed change gear 23, to thereby control the speed thereof. While an adjustable weight 125 is provided, because of lack of the factor of generating spark between the core wire and the sheave, as in the case of the first dancer roller, the weight of the weight 125 can be controlled to a minimum extent in a range permitting smooth vertical movement of the second dancer roller body 37.

Furthermore, the vertically displaced position of the body 37 can be detected by a detector 126. That is, a pair of brackets 127 are mounted on the upper and lower portions of the recessed portion 122, and the upper bracket has a short shaft 128 and the lower bracket has a bevel gear 129, and a rotary cylinder 140 with a cam 130 having a required torsional angle over its length is mounted therebetween. A pair of cum rollers 141 projecting backward from the body 37 engage the cam'l30 of the cylinder 140, and thereby when each of members 125,18, and the rest provided in the body 37 move vertically as a whole, the cam rollers 141 operate along the torsional angle of cam 130 to thereby rotate the rotary cylinder 140 about its central axis, and this rotation is transmitted to a shaft 143 having a bevel gear 142 engaging the bevel gear 129, and is further transmitted to a spur gear 145 of the detector 126 through a spur gear 144 provided on the other end of the shaft 143. Thus, the vertically displaced position of the second dancer roller body 37 is detected by the detector 126.

In order to prevent the core wire heated by the re heating apparatus from being cooled by the first capstan apparatus and the second dancer roller apparatus, described above, the first capstan and the second dancer roller are enclosed within a heat insulating wall, and a hot air generator is provided to supply hot air.

More particularly, in FIG. 10, a blower 146 moves air through a passage 147 having a heater 148 and a thermometer 149 disposed therein, and a heat insulating wall 150 surrounds the first capstan apparatus and the second dancer roller apparatus with an exhaust port 151 being provided in its upper end. The air fed from blower 146 into air passage 147 is heated by the heater 148 and fills the chamber insulated by heat insulating wall 150, then exits through exhaust port 151, thereby attaining the desired purpose.

The softened core wire W2 passes from the second dancer roller upper roller 17 through guide roller 19 mounted in the front of the extrusion coating station, and enters the extrusion coating phase, cooling and take-up steps, as is well known, to obtain an electric wire for use as communication cable.

While the driving system in each of the various apparatus described herein will now be described in detail, it can be provided into the following two driving systems, as is already clear.

That is, one of them is the driving system for the softening apparatus and the preheating apparatus, and the other is the driving system for the reheating apparatus and the first capstan.

The driving system for the softening apparatus and the preheating apparatus will be first described. In FIG. 3, the rotation of the first motor 20 is transmitted through the timing belt 152 to the timing pulley 153 on the intermediate shaft 33 to drive the wire drawing machine 1. Further, it is transmitted from the timing pulley 153 through the timing belt 154 to the first stepless speed change gear 22, and the peripheral speed of preheating sheave 4 is increased over the peripheral speed of drawn wire finishing capstan 4 by the first stepless speed change gear 22, and is transmitted through the V-belt 155 to the V-belt wheel 156 on the intermediate shaft 32, shown in FIG. 12.

The construction of the intermediate shaft 32 will be described with reference to FIG. 12, wherein 157 is a bearing support for the shaft, 158 isa timing pulley for driving the preheating sheave, 159 is a timing pulley for I driving the softening upper sheave, 160 is a timing pulley for driving the softening lower sheave, 161 is a V- pulley for driving the reheating apparatus and the first capstan apparatus, and 162 is a timing belt for transmitting power from the wire drawing machine. The power transmitted to the timing belt 162 is transmitted to timing pulleys 158, 159 and 160 by the shaft 32. The

power is transmitted from timing pulley 158 through belt 46 to timing pulley 45, shown in FIG. 4, and drives preheating sheave 4 fixed on shaft 25 rotatably sup ported by suitable bearings.

The power is transmitted from timing pulley 159 through timing belt 56 to timing pulley 55, shown in FIG. 5, and drives softening upper sheave 8 fixed on shaft 26 also rotatably supported by bearings.

Power is transmitted from timing pulley 160 through timing belt 64 to timing pulley 63, shown in FIG. 5, and drives softening lower sheave 9 fixed on the rotatable shaft 27.

In this event, each of the three timing pulleys 158, 159 and 160 is of the same diameter, and each of three timing pulleys 45, 55, 63 is of the same diameter. Since each of the preheating sheave 4, the softening upper v sheave 8 and the softening lower sheave is of the same diameter, the peripheral speed of each sheave is main tained the same.

The driving system for the preheating apparatus and the first capstan apparatus will now be described. The power of motor 21, shown in FIG. 3, is transmitted through Vbelt 102 to V-belt wheel 103, shown in FIG. 9, and drives shaft 29 and reheating lower sheave 14 fixed thereon. In normal operation, the clutch 112 is released, and the power is transmitted from timing pulley 104 fixed on shaft 29 through timing belt to timing pulley 92, and drives preheating upper sheave 13 fixed on shaft 28. Since each of the timing pulleys 104 and 92 is of the same diameter and each of the reheating sheaves 13 and 14 is of the same diameter, the peripheral speed of each sheave is maintained the same.

Power is then transmitted from timing pulley 106 fixed on shaft 29 through timing belt 107, shown in FIG. 3, to the second stepless speed change gear 23, and the peripheral speed of the first capstan sheaves 15 and 16 is increased over the peripheral speed of reheating lower sheave 14 by the second stepless speed change gear 23. Power is transmitted through timing belt to timing pulley 113, shown in FIG. 10, to drive the first capstan front sheave 15 fixed on shaft 30 and power is transmitted from timing pulley 114 through timing belt 121 to timing pulley 117 to drive the first capstan rear sheave 16 fixed on shaft 31.

Finally, the driving system during wire setting, briefly described above, will be described. In FIG. 9, clutch 112 is operated to connect shaft 29 and shaft 111. Power is transmitted from timing pulley 161 fixed on intermediate shaft 32, shown in FIG. 12, through timing belt 23 to speed change gear 24 for reversing the direction of rotation shown in FIG. 3, and after reversing the direction of rotation, is transmitted through belt 109 to pulley 110, and since wire drawing machine 1, preheating sheave 4, softening upper and lower sheaves 8 and 9, reheating upper and lower sheaves 13 and 14 and the first capstan front and rear sheaves 15 and 16 rotate as a whole, the wire setting operation can be performed smoothly.

As described above, according to the present invention, the softening apparatus including the tension stabilizing mechanism and the softening and preheating mechanism is provided between the heat treating step and the coating step, and, therefore, the breakage and quality degradation of electric wire during its manufac ture can be prevented, thereby sufficiently accomplishing the aimed purpose.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is to be understood, therefore, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. I

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A softening apparatus employed in the heat treating step in a tandem electric wire manufacturing process wherein wire drawing, heat treating, extrusion coating, cooling and take-up steps are performed in tandem, comprising:

a tension stabilizing mechanism for setting the tension of core wire in the heat treating step independently of the tension of the core wire in the subsequent steps, said tension stabilizing mechanism being formed of a first dancer roller, a second dancer roller and a first capstan between the first dancer roller and the second dancer roller.

2. A softening apparatus according to claim 1, further comprising a softening mechanism for elevating the temperature of the core wire to its softening temperature being disposed in advance of the first dancer roller.

3. A softening apparatus according to claim 2, further comprising a reheating mechanism for reheating the softened core wire being positioned between the first dancer roller and the first capstan.

4. A softening apparatus according to claim 3, further comprising a hot air generator for preventing the reheated core wire from cooling being positioned bea first driving system having a first motor for driving said softening mechanism and a first stepless speed change gear; and

a second driving system having a second motor for driving said first capstan and a second stepless speed change gear being independent of said first driving system.

6. A softening apparatus according to claim 5, further comprising a mechanism for controlling said first driving system by making a change in said first dancer roller and for controlling said first driving system and said second driving system by making a change in said second dancer roller.

7. A softening apparatus according to claim 5, further comprising clutch means for selectively connecting said first stepless speed change gear and said second stepless speed change gear.

8. A softening apparatus according to claim 1, further comprising a driving system for rotating a shaft supporting a sheave which does not transmit driving force to the core wire in synchronism with the rotation speed of the sheave, and a bearing mechanism positioned between the sheave and the shaft.

9. A softening apparatus according to claim 2, wherein the softening mechanism comprises a sheave constructed of a highly conductive material for passing current through the core wire.

10. A softening apparatus according to claim 3, wherein the reheating mechanism comprises a sheave constructed of a highly conductive material for passing current through the core wire.

11. A softening apparatus according to claim 5, further comprising a mechanism for controlling said first driving system and said second driving system by making a change in said second dancer roller. 

1. A softening apparatus employed in the heat treating step in a tandem electric wire manufacturing process wherein wire drawing, heat treating, extrusion coating, cooling and take-up steps are performed in tandem, comprising: a tension stabilizing mechanism for setting the tension of core wire in the heat treating step independently of the tension of the core wire in the subsequent steps, said tension stabilizing mechanism being formed of a first dancer roller, a second dancer roller and a first capstan between the first dancer roller and the second dancer roller.
 2. A softening apparatus according to claim 1, further comprising a softening mechanism for elevating the temperature of the core wire to its softening temperature being disposed in advance of the first dancer roller.
 3. A softening apparatus according to claim 2, further comprising a reheating mechanism for reheating the softened core wire being positioned between the first dancer roller and the first capstan.
 4. A softening apparatus according to claim 3, further comprising a hot air generator for preventing the reheated core wire from cooling being positioned between said first capstan and said second dancer roller, and said first capstan and said second dancer roller being surrounded by a heat insulating wall.
 5. A softening apparatus according to claim 2, further comprising: a first driving system having a first motor for driving said softening mechanism and a first stepless speed change gear; and a second driving system having a second motor for driving said first capstan and a second stepless speed change gear being independent of said first driving system.
 6. A softening apparatus according to claim 5, further comprising a mechanism for controlling said first driving system by making a change in said first dancer roller and for controlling said first driving system and said second driving system by making a change in said second dancer roller.
 7. A softening apparatus according to claim 5, further comprising clutch means for selectively connecting said first stepless speed change gear and said second stepless speed change gear.
 8. A softening apparatus according to claim 1, further comprising a driving system for rotating a shaft supporting a sheave which does not transmit driving force to the core wire in synchronism with the rotation speed of the sheave, and a bearing mechanism positioned between the sheave and the shaft.
 9. A softening apparatus according to claim 2, wherein the softening mechanism comprises a sheave constructed of a highly conductive material for passing current through the core wire.
 10. A softening apparatus according to claim 3, wherein the reheating mechanism comprises a sheave constructed of a highly conductive material for passing current through the core wire.
 11. A softening apparatus according to claim 5, further comprising a mechanism for controlling said first driving system and said second driving system by making a change in said second dancer roller. 